Detailed modeling of soot formation and destruction was carried out using a model which consists of a relatively large reaction gas phase mechanism and of a mechanistic soot model. The objective of the present study is to validate a comprehensive gas phase reaction mechanism for soot precursor species from experiments of sooting flames for pressures up to 15 bar and to identify dominant pathways in the soot model. From the simulation of experimental soot absorption profiles measured in rich premixed laminar ethylene/air flames at elevated pressures, dominant reaction steps are identified by sensitivity analysis. The response of the proper soot model with respect to variations of rate coefficient values of relevant reactions in the gasphase and in the particle inception and oxidation regime is investigated.